Automatic car safety device for electric elevators.



J. H. JOHNSON.

Patented Sept. 5, I899.

AUTOMATIC OAR SAFETY DEVICE FOR ELECTRIC ELEVATORS.

{Application filed July 11, 1899.)

No Model.)

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JAMES II. JOHNSON,

TO WILLIAM R. WEEKS,

AUTOMATIC CAR SAFETY DE PATENT OFEIQ OF NEIVARK, NEW JERSEY, ASSIGNOR OF ONE-HALE OF SAME PLACE.

VICE FOR ELECTRIC ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 632,651, dated September 5, 1899. Application filed my 11, 1899. Serial nmzsaev. (No model.)

To all whom it may concern:

Be it known that 1, JAMES H. JOHNSON, a citizen of the United States, residing at Newark, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Automatic Car Safety Devices for Electric Elevators,fully described'and represented in the following specification and the accompanying drawings, forming a part of the same.

The present invention relates to so-called electrical elevators in which an electric elevator is combined with a hoisting-drum and the car is elevated in the hoistway by a rope led from such drum. It is common in such constructions to furnish electrical connections and a lever for closing or reversing the circuit through the motor, so as to start or stop or reverse the movement of the car at pleasure, and a so-called pull-rope or its equivalent is connected with the car, so that the operator can control the operation of the motor from the moving car. In my application, Serial No. 714,669, filed April 27, 1899, for automatic safety-stop for elevators I have claimed an auxiliary device to wholly cut off the current from the motor in case the operator fails to control the movement of the car and it travels beyond its normal limit. The auxiliary appliances claimed in the said application are adapted only to stop the car at the extreme ends of its travel, and the present invention constitutes a modification of the same appliance by which it may operate to stop the car at any point in its movement when its velocity exceeds a predetermined limit. was provided with a block projected in the path of the car, so that a dog upon the car by contact with such block might actuate the shifter-rod and open a cut-out switch. In the present invention a governor is provided upon the moving car and its rotations controlled by the cars velocity, and a rope connected with the cut-out switch is pulled automatically when the governor exceeds the desired speed at any point in the cars movement.

The invention will be understood by reference tothe annexed drawings, in which- Figure 1 is a diagrammatic representation of a hoistway, car, and the required attachments; and Fig. 2 is an elevation of the car upon a larger scale.

mere equivalent for that m which it replaces.

In the former invention a shifter-rod of the car-body The 'fioors of the building are'designated a, the guide-posts b,the car 0, and the hoistingrope d. The rope-drum'is designated 6, the electric motor f, and the armature-shaft g.

2 denotes the controller-box provided with a controller-lever h to actuate the current-controlling mechanism of the motor. The usual pull-rope 7c is extended through'the car and across the hoistway to the opposite sides of the controller-wheel 2', which when the pull rope isoperated actuates thelever hby means of a cam j. These are ordinaryappliances and serve to operate the motor and'the car normally. I 7

The auxiliary safety appliances comprise a cut-out switch-lever l and'a safety-rope m extended through the hoistway'and actuated by clamps upon the car. The rope is secured to the opposite ends of a rod 2;, supported'in bearings 3 upon the guide-post b. The rod operates the same as if the rope was extended downwardly along the post, but as it replaces one-half of the rope it obviates the stretch which is liable to occur in'long ropes, and thus makes the safety device operate more promptly and effectively. The rod is a portion of the rope A block 4 is shown secured near the upper end of the rod o and a dog 5 upon the car to contact with the same to arrest the car if it passes beyond the normal limit of its travel; but the block 1 and dog 5 are not claimed herein, as they are shown and claimed in a separate application, Serial No. 714,669, filed April 27, 1899.

A clamp 19 is shown secured upon the side a with cams constructed to clamp the rope on when actuated by handle at. The cams are connected by segments 0*. A governor-clamp q is shown upon the top of the car connected with a governor s by levers t and Lt.

In Fig. 2 the clamps are disengaged from the rope m; but in Fig. 1, where only the outline of the clamp is shown, the clamp qis pressed upon the rope and the switch is opened by thepulling of the lever Z. The shifter-rod o is shown supported movably in guides 3 upon the left-hand post I) in Fig. 1, and the rope m is connected to the top and bottom of such rod. A block 4 is secured upon the rod near the top, and a dog 5 is attached to the car, which contacts with such block and shifts the rod o if the car passes beyond the upper limit of its travel, thus pulling the switch-lever Z and preventing the car from moving further by wholly cutting off the current from the controller 5. The

drum is thus prevented from winding up the ropes after the car reaches the top of the hoistway, which might result in the breakage of the ropes and the falling of the car.

The governor-pulley w is driven by rope y, fixed at the top of the hoistway and carried over the governor-pulley and over an idle pulley 00 upon the car, and provided at its lower end with a weight 0 to produce a constant tension. The weight hangs constantly at the bottom of the hoistway, as the pulleys w and a: are both supported upon the car and simply roll over the rope as the car moves up or down.

The operation of these appliances is as follows: The car, so long as it is controlled by the pull-rope 70, moves at a normal speed up or down the hoistway, but when through any accident or derangement of the machinery the pull-rope fails to control the car and the latter assumes any abnormal speed the governor actuates the governor-clamp and grips the safety-rope, which immediately pulls the cut-out switch-leverZ and cuts off the current from the electric motor. This brings the motor to rest and avoids further movement of the car. Should the governor fail to operate properly the hand-lever n in the car still remains as a means of operating the cutout switch, as it serves positively, it moved by the operator, to press the clamp 19 upon the safety-rope and thus cut off the current from the motor.

From the above description it will be understood that my safety appliances are auxiliary or additional to the controller for normally regulating the movement of the car, and are intended only to operate when the car assumes an abnormal speed or the operator is unable to control its movements by the ordinary pull-rope. Where an electric switch is placed upon the car and connected with the controller of the motor, it of course performs the same function as the pull-rope k, which I have shown and described herein, and my safety appliances would be additional or auxiliary to such electrical con trolling apparatus.

The safety-rope m is practically an endless rope,like an ordinary pull-rope, as its two ends are connected to the switch-lever Z, and loops of the rope are extended upwardly and downwardly in the elevator-shaft, so that a straight portion of the rope traverses the entire path of the moving car. By connecting both ends of the rope with the switch-lever Z the clamp when operated pulls the switch-lever to open the elecric circuit, whether the car be moving upward or downward, and the car is thus stopped automatically whenever its speed is excessive. The positive and negative wires .of the electric circuit are shown connected with the auxiliary switch and with the controller z, and the circuit-lever is so drawn as to make the breaking of the circuit apparent to the eye. By using the endless rope m the pull upon one end of the rope required to shift the switch-lever produces a corresponding slackness at the other end of the rope, which is indicated by the curved position of the upper rope end where connected with the switch-lever.

It is obvious that the constructive features may be modified to suit the particular relation of the electric motor to the hoistway, the essential features being the auxiliary switch for cutting 06 the current from the motor and the safety-rope extended therefrom up the hoistway, with a governor upon the car and clamp to grip the rope when the governor is rotated abnormally fast.

Having thus set forth the nature of the invention, what is claimed herein is 1. In an elevator, the combination, with the hoistway and the car movable therein, and an electric motor, drum, and rope for hoisting the car, with controller for normally regulating the movements of the motor, of an auxiliary switch for cutting oi the current from the controller, a safety-rope extended in the hoistway and connected to such auxiliary switch, and a governor upon the car with clamp actuated by the governor, when rotated abnormally fast, to grip the said rope and thus open the switch to stop the motor.

2. In an elevator, the combination, with the hoistway and the car movable therein, and an electric motor, drum, and rope for hoisting the car, with controller for normally regulating the movements of the motor, of an auxiliary switch for cutting off the current from the controller, a safety-rope extended up and down the hoistway with both ends connected to such switch-lever, and a governor upon the car with clamp actuated by the governor, when rotated abnormally fast, to grip the said rope, and thus open the auxiliary switch whichever way the car may be moving.

3. In an elevator, the combination, with the hoistway and the car movable therein, and an electric motor, drum, and rope for hoisting the car, with controller for normally regulating the movements of the motor, of an auxiliary switch for cutting off the current from the motor, a safety-rope extended in the hoistway and connected to such auxiliary switch, a governor upon the car with clamp to grip the said rope, and a hand-clamp with handle inside the car, whereby the auxiliary switch may be opened when the car moves abnormally fast, or at the pleasure of the operator, substantially as herein set forth.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

JAMES H. JOHNSON. Witnesses:

THoMAs S. CRANE, I. L. MCCLOUD. 

